Marx believed this unresolved phenomena would lead to violent revolution, Lenin only added his analysis of Capitalism's evolution into Imperialism, and his theory of Revolution, which focuses on the idea of the most radical workers forming a vanguard to bring the other workers up and help direct them. Marx believed the Revolution would happen and from it Socialism would emerge, hence him advocating for "siezing the Means of Production." He also pointed directly to the Paris Commune, a hostile takeover of government aparatus, as the Dictatorship of the Proletarait he advocated for in action.

Lenin wasn't just "hey, let's ignore Marx and do this at gunpoint," it was more "hey, let's listen to Marx, and do this at gunpoint." Lenin actually addresses this utter de-fanging of Marx in bourgeois society in the opening section of The State and Revolution:

"What is now happening to Marx’s theory has, in the course of history, happened repeatedly to the theories of revolutionary thinkers and leaders of oppressed classes fighting for emancipation. During the lifetime of great revolutionaries, the oppressing classes constantly hounded them, received their theories with the most savage malice, the most furious hatred and the most unscrupulous campaigns of lies and slander. After their death, attempts are made to convert them into harmless icons, to canonize them, so to say, and to hallow their names to a certain extent for the “consolation” of the oppressed classes and with the object of duping the latter, while at the same time robbing the revolutionary theory of its substance, blunting its revolutionary edge and vulgarizing it. Today, the bourgeoisie and the opportunists within the labor movement concur in this doctoring of Marxism. They omit, obscure, or distort the revolutionary side of this theory, its revolutionary soul. They push to the foreground and extol what is or seems acceptable to the bourgeoisie. All the social-chauvinists are now “Marxists” (don’t laugh!). And more and more frequently German bourgeois scholars, only yesterday specialists in the annihilation of Marxism, are speaking of the “national-German” Marx, who, they claim, educated the labor unions which are so splendidly organized for the purpose of waging a predatory war!"

As for the USSR, it wasn't totalitarian. Workers did have control, there were no real bourgeois elements, no competing markets, and the state was not an "other" compared to the Workers. They had democratic measures in the form of Soviets, and the consequences of this were free education, healthcare, high home ownership rates, and so forth. Was the USSR perfect? Absolutely not, but it was history's first major attempt at Marxist Socialism, and we can study it for that. The revolution wasn't "hijacked," it was led by the Workers and continued to be until corruption took hold over time and the USSR collapsed, being hacked up and sold for parts as a part of "Shock Doctrine," plumetting life expectancy, GDP, and causing 2 million excess deaths.

Co-operatives are met with hostile action because it's easy to crush them when you have the state and monopoly on your side, hence why they will never likely be a leading force for Socialism within Capitalism, even if they should still be supported by Socialists everywhere.